Jamming System to Prevent Hacking of Cardiac Implants

Ever since researchers have demonstrated that hacking implantable cardiac devices is a theoretical possibility, there’s been a fear going around that someone will actually go through with the evil act and kill some people. To prevent this possibility, researchers from MIT and the University of Massachusetts-Amherst have developed a wireless filter that will jam all signals on a given frequency except those that have been authorized by its encryption system. The researchers envision that in the future, implant wearers will have a separate device on their body that manages wireless access to the implant. In an emergency, though, paramedics will be able to quickly remove this filter and be able to quickly access the implant.

More from an MIT announcement:

Because the jamming transmitter, rather than the implant, would handle encryption and authentication, the system would work even with existing implants.

The key to the system, Katabi [Dina Katabi, associate professor in MIT’s Department of Electrical Engineering and Computer Science] explains, is a new technique that allows the shield to simultaneously send and receive signals in the same frequency band. With ordinary wireless technology, that’s not possible: The transmitted signal would interfere with the received signal, rendering it unintelligible. Researchers at Stanford University recently demonstrated a transmitter that could send and receive at the same time, but it required three antennas whose distance from each other depended on the wavelength at which they were operating. For medical-device frequencies, the antennas would have to be about a half a meter apart, making it impossible to miniaturize the shield.

The MIT-UMass system uses only two antennas and clever signal processing that obviates the need to separate them. “Think of the jamming signal that we are creating as a secret key,” Katabi explains. “Everyone who doesn’t know the secret key just sees a garbage signal.” Because the shield knows the shape of its own jamming signal, however, it can, in effect, subtract it from the received signal.